U.S. President Barack Obama has warned his Chinese counterpart that the United States would not be able to keep Israel from attacking Iranian nuclear installations for much longer, senior officials in Jerusalem told Haaretz.

They said Obama warned President Hu Jintao during the American’s visit to Beijing a month ago as part of the U.S. attempt to convince the Chinese to support strict sanctions on Tehran if it does not accept Western proposals for its nuclear program.

After the Beijing summit, the U.S. administration thought the Chinese had understood the message; Beijing agreed to join the condemnation of Iran by the International Atomic Energy Agency only a week after Obama’s visit. But in the past two weeks the Chinese have maintained their hard stance regarding the West’s wishes to impose sanctions on the Islamic Republic.

The Israeli officials say the Americans now understand that the Chinese agreed to join the condemnation announcement only because Obama made a personal request to Hu, not as part of a policy change.